The present invention relates to an apparatus for efficient wet treatment of a plural number of wafer materials, e.g. wafers of a silicon semiconductor, with a chemical etching solution or other liquids.
As is well known, wafers of silicon semiconductors are usually subjected to one or more of wet-process treatments such as chemical etching treatment by use of a treatment liquid, e.g. etching solution, in the course of processing into semiconductor devices. In the simplest prior art, such a treatment of chemical etching is carried out by placing the wafer materials one by one in a container such as a basket and by dipping and gently shaking the basket holding the wafers in the treatment liquid, e.g. etching solution. After the end of the chemical etching, the basket is taken out of the etching solution and rinsed in water in a similar manner.
As the number of the wafer materials to be treated in the wet process as described above is increased more and more, such a hand work is no longer practical because not only the hand work is very tedious and inefficient and involves a problem of safety or health of the workers caused by the sometimes toxic treatment liquids but also uniformity or reproducibility cannot be ensured in the effects of the treatment. Accordingly there have been several proposals for the mechanization of the wet-process treatments of wafer materials but none of the machines hitherto proposed can give satisfactory results due to the complicacy in the structure thereof.